Created with TaskStream 4: Measurement: Using a Balance to Weigh
Author: Maya Creedman
Date created: 11/19/2002 5:59 PM PDT

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General Comments
Westminster Magnet
Grade Level
Grade 3
Students enjoy hands-on activities. English Language Learners need to see and experience concepts.
Subject Area(s)
Students will learn to use a scale, estimate and measure objects using grams.
How can you find out how much an object weighs?

CA- California K-12 Academic Content Standards
Subject: Mathematics
Grade: Grade ThreeBy the end of grade three, students deepen their understanding of place value and their understanding of and skill with addition, subtraction, multiplication, and division of whole numbers. Students estimate, measure, and describe objects in space. They use patterns to help solve problems. They represent number rela-tionships and conduct simple probability experiments.
Area: Measurement and Geometry
Sub-Strand 1.0: Students choose and use appropriate units and measurement tools to quantify the properties of objects:
Standard 1.1: Choose the appropriate tools and units (metric and U.S.) and estimate and measure the length, liquid volume, and weight/mass of given objects.
Area: Mathematical Reasoning
Sub-Strand 2.0: Students use strategies, skills, and concepts in finding solutions:
Standard 2.1: Use estimation to verify the reasonableness of calculated results.
Given a balance and working in pairs, students will weigh and record classroom objects including beans for an experiment using gram pieces with 90% accuracy.

Students' estimation of objects will improve as the activity progresses.
Prerequisite Background Skills/Knowledge
Students need to have procedures for working in groups. Students need to understand the need for a standard in measurement and why we measure.
Vocabulary / Language Skills
The teacher models steps of weighing an object and clearly identifies each new part by showing, speaking the name and writing the name on the Structures of Life Word Bank chart. The meanings of the words mesurement, weight, grams, balance, scale and estimation are reviewed.
balance, plastic cups
gram pieces
weighable objects
lima beans
recording sheets/ pencils
Classroom Management
Teacher requires students to complete one step, before moving on the next step. The teacher constantly circulates classroom to monitor procedures.
The teacher writes the word "measurement" on the board and asks the students to name all the words they can think of that have to do with measurement. The teacher prompts the students to think about the ways they could measure the changes in their seeds.
The teacher groups the students responses into categories of the different kinds of measurement: length, weight and volume. The teacher asks the students how the students could measure the amount of water that soaks into a lima bean overnight.
The teacher tells the students that in order to weigh the lima beans they will need to have a standard way to measure.
The teacher demonstrates for the class weighing a lima bean using paper clips. Because their are more than one size of paper clips there is no way to get an accurate measurement.
The teacher tells students that their are standard amounts of weight that are always the same and one standard is grams. The teacher shows the students the gram pieces and tells them they are going to learn how to use the scale.
The teacher asks the students to name some things they could measure that would fit into a cup and writes them on the board. The teacher then passes out a sheet of paper with the eight steps of weighing on it out of order to each group. The teacher tells the students that they will need to put the steps in the right sequence in order to get their balance and begin weighing objects.
The teacher models the correct weighing procedure while saying the steps in the correct sequence. The groups then work together to put the steps in the right order. When the group has finished, the teacher allows the group to get their scales.
The teacher hands out a sheet for students to record classroom object, estimated measurement, exact measurement and difference between estimated and exact measurement. The teacher gives directions and allows pairs to begin working. First, students must list three objects they want to measure. Second, students must make an estimate of how many grams the first object weighs. Then they weigh and record the measurement and the difference. Then they repeat the steps with the next object.
The teacher circulates around the pairs to ensure that students are using the correct procedure. The teacher takes informal notes.
The teacher asks students if their estimation has improved. The teacher then tells students they are ready to measure the lima beans for their next science experiment. The students in each group estimate and measure the lima beans carefully. The groups compare and discuss results. Why might measurements be slightly different between groups? Students record measurements and write in their journal a response to the following questions: What did you learn about measurement today? What do you think the beans will weigh tomorrow after we soak them in water? Why?
informal notes/checklist for each student to ensure student participation, use of weighing procedures and estimation accuracy and class disscussion

student worksheets are collected and checked for accuracy
The hands-on and relevant nature of this investigation created a highly motivated and engaged group of students. Students paid attention to the weighing procedures and worked hard to get it right so they could begin to weigh things. Most of their estimations began to improve as they compared their estimations with the actual measurement. The students were then able to connect what they had learned to their current investigations in science. The only change I would make next time is to separate this activity into two parts to provide students with a little longer time to experiment. I would also provide an even wider variety of objects for students to weigh at each table.